661616619 has 16 divisors (see below), whose sum is σ = 917980800. Its totient is φ = 423513216.

The previous prime is 661616611. The next prime is 661616633. The reversal of 661616619 is 916616166.

It is not a de Polignac number, because 661616619 - 2³ = 661616611 is a prime.

It is a super-2 number, since 2×661616619² = 875473101073982322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661616611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35854 + ... + 51075.

It is an arithmetic number, because the mean of its divisors is an integer number (57373800).

Almost surely, 2^661616619 is an apocalyptic number.

661616619 is a deficient number, since it is larger than the sum of its proper divisors (256364181).

661616619 is a wasteful number, since it uses less digits than its factorization.

661616619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87034.

The product of its digits is 69984, while the sum is 42.

The square root of 661616619 is about 25721.9093187112. The cubic root of 661616619 is about 871.3690599574.

The spelling of 661616619 in words is "six hundred sixty-one million, six hundred sixteen thousand, six hundred nineteen".